Fabrication of n‐Type Doped V‐Shaped Structures on (100) Diamond

Christoph Schreyvogel,Christoph E Nebel,Julien Barjon,Solange Temgoua,Christian Giese,Volker Cimalla

doi:10.1002/pssa.202000502

Abstract

Herein, a technological process for the fabrication of n‐type doped V‐shaped structures on (100) single‐crystalline diamond substrates, designed to overcome the limitations of n‐type doping on (100) surfaces, is presented. This doping enhancement process can be applied to realize electronic power devices such as a junction barrier Schottky diode or junction field effect transistors with low on‐resistance. Herein, a catalytic etching process is performed by using square‐shaped nickel masks on the diamond surface and annealing in a hydrogen atmosphere, resulting in the formation of inverted pyramidal structures with flat {111} sidewalls. The resulting V‐shaped structures are subsequently overgrown with phosphorus‐doped diamond to achieve n‐type doped facets with higher doping concentrations. Cathodoluminescence studies reveal the predominant incorporation of phosphorus donors on the {111} sidewalls of V‐shaped structures.

Highlights

Introduction mond is preferred many unipolar and bipolar power devices have been developed since the full performanceDiamond has outstanding physical and electronic properties, potential of these devices has yet to be realized, partially because rendering it an attractive material for fabricating next-generation of the high resistivity of n-type doped diamond films, which wide-bandgap devices
Using cathodoluminescence (CL), we demonstrate the predominant incorporation of phosphorus donors on the {111} sidewalls
A diamond sample with a Ni film on the surface was exposed at elevated temperatures (850 C in this case) to a hydrogen atmosphere

Summary

Basic Mechanism of Catalytic Etching of Diamond

This etching anisotropy observed for diamond is comparable with the chemical etching of silicon with KOH solutions This theory of etching mechanism, which is described above, can be deduced from the following experimental evidences published in the literature and summarized in the following.[17,18] First of all, when a diamond film with a Ni mask on the surface is annealed in vacuum, i.e., without a hydrogen atmosphere, there is no desorption of carbon dissolved in the Ni film. This leads to the formation of a nucleated carbon layer in the Ni film measured with energy dispersive X-ray analysis (EDX). This plane appears to be rougher than the {111} facets and has more defects

CL Studies

Conclusion

Experimental Section

Data Availability Statement